If you get the right Z170 mobo with the right (older) BIOS, yes you can overclock. Whether it's worth it is debatable. Although, if you are going to overclock a non-k CPU, you might as well get the cheaper i5-6400.
http://overclocking.guide/category/intel-oc-guides/skylake-non-k-oc/
Edit
Supernova1138 it's not just ASRock mobos that supported non-k OC. And you can always just down-grade the firmware if you get a mobo with a newer rev that blocks non-k OC.